Centrifuges



Oct. 2, 1962 N. v. ANDERSSON 3,056,505

CENTRIFUGES Filed Oct. 20, 1959 4 Sheets-Sheet 1 Fig.1

l/WEIVTOR NILS VILHELM ANDERSSON 1962 N. v. ANDERSSON 3,

CENTRIFUGES Filed Oct. 20, 1959 4 Sheets-Sheet 2 Fig. 2

lA/VE/VTOR NILS VILHELM ANDERSSON Oct. 2, 1962 N. v. ANDERSSONCENTRIFUGES 4 Sheets-Sheet 3 Filed Oct. 20, 1959 INVENTOR NILS VILHELM.ANDERSSON Oct. 2, 1962 N. v. ANDERSSON CENTRIFUGE'S 4 Sheets-Sheet 4Filed 001;. 20, 1959 l/VVE/VTOR NILS VILHELM ANDERSSON United StatesPatent Ofifice 3,056,505 Patented Oct. 2, 1962 3,056,505 CENTRIFUGESNils Vilhelm Andersson, Landskrona, Sweden, assignor to AktiebolagetLandsverk, Landskrona, Sweden, a corporation of Sweden Filed Oct. 20,1959, Ser. No. 847,541 Claims priority, application Sweden July 24, 1959Claims. (Cl. 210-369) The present invention relates generally todiscontinuously operating centrifuges and particularly relates to acut-off valve for a central outlet opening at the bottom of thecentrifugal drum, through which the material, such as sugar crystals,subjected to centrifugal treatment may be discharged from thecentrifugal drum. Valves for opening and closing the discharge openingof a cen trifuge are known. They frequently consist of a conical funnelplaced upside down above the outlet opening or openings. The funnel issecured to a sleeve, which may be displaced manually or by means of apneumatic operating contrivance along the spindle carrying the drum.When the funnel is in its lowermost position, the bottom openings of thedrum are closed, so that the filling mass or pulp which is to besubjected to centrifugal treatment may be supplied, without the liquidin the filling mass discharging down through the bottom openings. Whenthe funnel is then raised to its upper position upon the termination ofthe centrifugal treatment, the material subjected to the treatment maybe scraped off by means of an excavator of known type, and allowed tofall down through the outlet opening in the bottom of the drum, so thatanother charge of the material may be treated. It has been found that intreating baking material, that is to say vault-building material, suchas sugar of a high degree of purity, the material forms vaults from thecovering tunnel to the inner surface of the drum or to the materialremaining in the drum, so that the material cannot be scraped off bymeans of the excavator and be removed through the bottom openings.

These difiiculties are avoided according to the invention by making thecut-off valve member comprising a deformable, preferably flexible andelastic body, that is a diaphragm, which is secured to a sleeve andadapted axially displaceable on the drum driving spindle to be deformedby the displacement of thesleeve along the spindle of the drum in amanner such as to cover the bottom opening in its entirety, when thesleeve assumes its lower position. Whereas when the sleeve assumes itsupper position, the valve body has so small a diameter that the materialmay pass between the valve body and the inner surface of the drum or thematerial remaining in the drum without building any vaults.

According to one embodiment of the cut-off valve, a sprayer screen isarranged on the sleeve above the diaphragm' The screen is adapted, inthe filling of the drum with material, to throw a portion at least ofthe filling mass directly out against the inner surface of the drum,Without the filling material first touching the diaphragm.

The invention will be described in more detail with reference to theaccompanying drawings, which illustrate a centrifugal drum provided witha cut-off valve according to the invention and in which:

FIG. 1, is a vertical view of a centrifuge partly in section providedwith a valve according to the invention;

FIG. 2, is a fragmentary view on an enlarged scale of a vertical view ofthe valve of the invention;

FIG. 3, is a plan view of the valve;

FIG. 4, is a fragmentary section through a portion of the diaphragm andits supporting plates in an expanded position of the diaphragm;

FIG. 5, is a fragmentary section of the diaphragm, illustrating itsfolded position; and

FIG. 6, is an axial section through a modified construction of thediaphragm.

According to the drawing a centrifuge provided with the inventioncomprises a centrifugal drum or bowl I mounted with a driving spindle 2extending axially into the bowl and a driving motor 3 for driving thespindle mounted on a frame consisting substantially of a girder system 5arranged on feet 4. The cylindrical surface of the drum is perforatedand provided on the inside thereof with a strainer cloth 6. It iscovered by a cover 7 underneath of which an excavator-not shown in thedrawing-is arranged for digging out the material gathered on a strainerdrum in the form of a cylinder 8. At the bottom 9 of the bowl 1 areprovided central outlet openings 10, through which the excavatedmaterial may fall downwardly and be discharged from the bowl. Theseopenings are adapted to be closed by means of a cut-off valve in theform of a diaphragm 14, which is carried by a sleeve 11 rotatable withthe driving spindle 2. The sleeve is provided at the top with a flange12 and at the bottom with a cone 13 secured to the sleeve 11 and inwhich the diaphragm 14 is inserted. The sleeve 11 is axially slidable onthe spindle and is carried by a roller 16 supporting the flange 12. Theroller is arranged on an arm 15, which may have a vertical movementimparted thereto by a pneumatic cylinder 17, so that the sleeve 11 withthe cone 13 is raised in a direction away from the opening into theposition indicated by dotted or broken lines in FIG. 1.

As will appear from FIGS. 25, the diaphragm 14 consists of a circulardisk of a flexible material, preferably rubber, which is braced by anumber of radial struts 19, which are pivotally connected at one endwith the cone 13, as at 18, and at the other end with levers or links 20pivotally secured to the spindle 2. These links radially expand thediaphragm in response to downward travel of said :sleeve 11 and radiallycontract it inwardly in response to upward travel of said sleeve ashereafter described. The links 20 have one end thereof connected to aring 24 movable axially on the lower large diameter portion of thespindle. When the sleeve moves upwardly the upward travel of the ring islimited by a stop 25 so the diaphragm is collapsed radially inwardly asshown in FIG. 2. In addition, the diaphragm is stiffened by means ofrigidifying members comprising sector shaped supporting plates 21radially arranged on the upper side thereof. These plates are riveted tothe respective struts 19 and have a curved configuration with a concavelower side and form rigidified sectors on the diaphragm as illustratedin FIG. 3.

In the position shown in solid lines in FIG. 2, the diaphragm has aslightly conical shape with an apex portion circumferentially of saidsleeve and a base portion thereof has so large a diameter that aperipheral marginal edge portion seats on a circular valve seat formedby the bottom 9 coaxial with the bottom opening or openings to cover theoutlet openings :10 in their entirety. When the sleeve 11 is raisedselectively in a direction away from its seat for opening the valve, thediaphragm is contracted radially inwardly so that the parts 19, 20 and21 will take the positions indicated by broken lines. The portions ofthe diaphragm lying between the sectors formed by the supporting plates21 will thus be folded in the manner shown in FIG. 5. The concavity ofthe supporting plates imparts to the intermediate portions a tendency toflex inwardly. In its collapsed position, the diaphragm has a diametersmall enough to permit the centrifuged material to pass out thrciugh theopenings 10 without any risk of forming vau ts.

Another construction of the diaphragm and associated parts is shown inFIG. 6. In this construction the outer part of the diaphragm 22 isdouble-folded and stiffened by means of resilient insets of steel wires,for example, so as to bear with a resilient pressure in its closedposition on the inner edge portion of the bottom 9 and to seatthereagainst, while in the open position it assumes the positionindicated by broken lines in the figure.

As shown in FIG. 1, the valve device may be provided with a sprayerscreen 23 secured to the sleeve 11. This screen is adapted, in thefilling of the centrifuge, to throw at least a portion of the fillingmaterial out against the inner side of the centrifugal bowl duringfilling of the centrifuge. Consequently, the filling material does nothit the diaphragm 14. This arrangement is of particular advantage inconnection with filling materials which are otherwise difiicult todistribute along the inner surface of the bowl 1.

What is claimed is:

1. In a centrifuge having a driven bowl having a bottom provided with acentral discharge opening and circular valve seat coaxially with saidcentral opening in said bottom, a driving spindle extending axially intosaid bowl, a sleeve axially slidable on said spindle, a valve membercomprising a collapsible conical diaphragm having an apex portionmounted circumferentially of said sleeve for axial travel therewith anda base portion comprising a peripheral marginal edge portion movableradially outwardly of said sleeve selectively into a position seated onsaid circular valve seat, means for selectively axially displacing saidsleeve axially on said spindle, means responsive to said axialdisplacement of said sleeve for contracting the diaphragm radiallyinwardly to uncover said discharge opening when the sleeve is moved in adirection away from said seat and for expanding the diaphragm andcausing said edge portion to seat on said valve seat thereby to closesaid opening when the sleeve is moved axially in the opposite directionon said spindle, and said means responsive to said sleeve displacementbeing arranged internally of said conical diaphragm.

2. In a centrifuge having a driven bowl having a bottom provided with acentral discharge opening and circular valve seat coaxially with saidcentral opening in said bottom, a driving spindle extending axially intosaid bowl, a sleeve axially slidable on said spindle, a valve membercomprising a collapsible conical diaphragm having an apex portionmounted circumferentially of said sleeve for axial travel therewith anda base portion comprising a peripheral marginal inner edge portionmovable radially outwardly of said sleeve selectively into a positionseated on said circular valve seat, means for selectively axiallydisplacing said sleeve axially on said spindle, means responsive to saidaxial displacement of said sleeve for contracting the diaphragm radiallyinwardly to uncover said discharge opening when the sleeve is moved in adirection away from said seat and for expanding the diaphragm andcausing said edge portion to seat on said valve seat thereby to closesaid opening when the sleeve is moved axially in the opposite directionon said spindle, said means responsive to said sleeve displacement beingarranged internally of said conical diaphragm, and angularly spacedrigidifying members fixed angularly spaced on said diaphragm formingrigidified sectors thereon corresponding to said members.

3. In a centrifuge according to claim 2, including means pivotallyconnecting said rigidifying members to said sleeve.

4. In a centrifuge according to claim 2, in which said rigidifyingmembers are arcuate in cross-section to assist in forming radiallyextending folds in said conical diaphragm when said valve member ismoved radially inwardly toward said sleeve.

5. In a centrifuge according to claim 2, in which means responsive tosaid axial displacement of said sleeve comprises a plurality ofangularly spaced links disposed extending radially inwardly toward saidspindle, means pivotally connecting one end of each link to thediaphragm and means pivotally connecting the opposite end of each linkto a point adjacent the periphery of said spindle, and means allowingthe last-mentioned pivot means to travel axially a relatively lesserextent than said sleeve travels when displaced and in response andcorrespondence in time and direction with said sleeve displacement.

References Cited in the file of this patent UNITED STATES PATENTS706,441 McLaughlin Aug. 5, 1902 2,037,655 Roberts Apr. 14, 19362,890,716 Werder June 16, 1959

